Field of the Invention
The present invention relates to planetary gear devices that are used for power transmission mechanisms for general industrial machinery, aircrafts, and the like, and that include a structure for distributing lubricating oil flow.
Description of Related Art
In recent years, one of the key issues in general machinery is to reduce fuel consumption from the viewpoint of reduction in operation cost and environmental conservation. Therefore, also for planetary gear devices for use in aircraft engines, reduction in power loss is required.
Conventionally, this type of planetary gear device includes a mechanism for supplying lubricating oil to gears in order to lubricate and cool the gears. However, one of main causes of power loss in the planetary gear device is stirring resistance of supplied lubricating oil. The stirring resistance of lubricating oil is proportional to the third power of a circumferential speed of a gear. Therefore, the stirring resistance becomes too high to be ignored in gears having high circumferential speeds. One example of a technique for reducing such stirring resistance of lubricating oil is disclosed in Patent Document 1. According to Patent Document 1, baffle units are provided in circumferential gaps formed between a plurality of planet gears to introduce, into the baffle units, excess lubricating oil that is generated around the adjacent planet gears after lubrication, and discharge the excess lubricating oil to the outside of the gear device. Thus, the stirring resistance of the lubricating oil is reduced, whereby power loss is reduced.